Insulated Facade System

ABSTRACT

The invention concerns a building façade having an inner wall, an insulation layer, an outer cladding layer and profiles for securing the outer cladding to the inner wall. Air gab for ventilation is provided between the insulation layer and the outer cladding. The insulation layer comprises insulation panels having two major large surfaces and four minor edge surfaces and the insulation panels have layers of insulation of different densities extending parallel to the two major surfaces, where a layer with a density above an average density of the panel is facing the outer cladding.

The invention concerns a ventilated building facade as described in thepreamble of claim 1. Furthermore the invention concerns an insulationpanel to be used in the ventilated façade, a method for providing such abuilding façade and a method for manufacturing insulation panels.

It is known to build a façade comprising an inner wall of e.g. concreteor bricks, an insulation layer of any type of insulation, an outercladding layer of e.g. tiles, wood, metal, boards of compressed fibresetc. Furthermore the façade comprises profiles fastened to the innerwall extending through the insulation layer and used for securing theouter cladding layer. The profiles extend vertically from ground leveland to the top of the building. During construction the profiles will besecured to the inner wall, and afterwards the insulation is arrangedbetween the profiles. Finally the outer cladding layer is secured to theprofiles. The outer cladding layer is made as boards, which are oftenplaced with small gabs in between the boards in order for ventilationair to be able to pass.

All types of insulation may be applied in such a façade system. However,often fibrous insulation materials such as mineral wool are preferred.Also for fire safety reasons especially stone wool or glass woolinsulation materials are preferred. The insulation may be in rolls or inthe form of panels or boards. When glass wool has been used it has beenin the form of rolls with a density around 18 kg/m³. Stone wool hasusually been used in the form of panels with a density around 40 kg/m³.Low density insulation is usually preferred due to the price. This alsomakes handling and transport on the building site easier.

One problem with these relatively low densities of the insulationmaterials is that more fasteners are needed in order to make theinsulation fit closely against the inner wall. A close fitting isimportant for ensuring optimal heat insulating capacity, and also forpreventing the ventilation gap from being blocked.

This problem could be solved by applying an insulation material with ahigher density. This will improve the rigidity of the insulation.However, some of the advantages of having low density insulation will belost, and such a solution will also increase the costs for theinsulation.

Another problem is that the soft insulation layer is more sensitive tomechanical damages during installation on the surface facing the outercladding layer. Furthermore, the surface of the low density insulationis less resistant to weather influence. Especially for higher buildingsthe action of wind and precipitation, e.g. rain, may be significant, andalso the precipitation may easily penetrate the openings for ventilationin the outer cladding layer. These two problems could be solved byapplying an insulation material with a higher density as this wouldresult in a more resistant surface.

It should be noted that the air gab for ventilation is essential forkeeping the temperature of the building as low as possible in the summertime. The radiation from the sun on the external cladding can bring thetemperature on this surface up to 60-70 degrees Celsius or more andwithout air gab this would also be the temperature of the outer surfaceof the insulation. Preferably there are also openings for ventilationair in the outer cladding layer. When having the air gab, and especiallywhen also having the openings in the outer cladding, the outer surfacetemperature of the insulation is more or less equivalent to the airtemperature which is often significantly lower than that of the outercladding layer. Thus the air gab ensures a lower temperature gradientacross the insulation layer and thereby a reduced heat flow into thebuilding during summer time. Furthermore, it ensures that any humiditywill dry out. It is essential that the insulation panels aresufficiently rigid and/or are supplied with a sufficient amount offasteners to prevent the insulation from bending out from the inner walland blocking the ventilation air gab.

Another known method for improving mechanical properties of theinsulation layer is to provide the mineral wool with a fleece layer(e.g. glass fibre fleece) on the outer surface. This will improve themechanical properties of the surface and reduce the risk of mechanicaldamage. A fleece layer will also improve the resistance to thedisintegration of the insulation caused by weather. However, a fleecelayer is a relatively expensive solution, and it does not increase thestiffness of the insulation layer much, and therefore a high number offastening means is still necessary.

The objective of the present invention is to obtain a more rigidinsulation material with a surface being resistant to mechanical actionand the influence of weather without sacrificing the advantageous of thepresently used low density insulation.

This has been solved by a ventilated façade comprising insulation panelshaving layers of insulation of different densities where a layer with adensity above the average density is facing the outer cladding layer.

The advantage of this new solution is that the higher density of theouter surface layer will provide the mechanical rigidity of theinsulation layer facilitating a reduced number of fasteners and it willalso provide good resistance against mechanical damages as well asagainst weather influences.

One further problem with the existing solution is that when installingsuch a façade system there will often be a tolerance on the distancebetween the profiles for holding the outer cladding layer. Thistolerance may cause a difference in the distance between the profilesfrom ground level to the top of a building. This difference could be afew centimetres (e.g. from 53 cm to 55 cm) making it difficult to attacha closely fitting insulation layer.

Further to this tolerance the necessary distance between the profiles inorder to comply with different standards for dimensions of the panelsfor the outer cladding layer may vary from e.g. 54 to 61 cm. So in orderto limit the number of different insulation dimensions manufactured itis necessary that one dimension of the insulation panels can be used foran interval of distances between the profiles.

Therefore in a preferred embodiment of the invention the insulationpanel is provided with a flexible zone along at least one edge surfaceso that the insulation panel is flexible in at least one direction andcan be fitted closely against limiting surfaces. The advantage of thisembodiment is that the edge flexibility ensures close connection betweenthe insulation layer and the profiles.

Profiles are attached to the inner wall and extend through theinsulation layer. The profiles provide a basis to which the outer coverlayer is secured. Usually T-profiles will be applied for this purpose,but L profiles or C profiles or other types could also be applied. Theseprofiles will usually be made of metal, preferably aluminium, but alsosteel, e.g. stainless steel, may be applied. The profiles could also bewooden beams.

When T-profiles are applied the thickness of the material will depend onthe weight of the outer cladding layer. The width of the base portionfixed to the inner wall and holding the flange portion depends on thethickness of the insulation panels and the thickness of the ventilationair gab.

When profiles provided with flanges for securing the outer claddinglayer are provided, insulation panels with a flexible zone offer theadvantage of being easier to install. This is due to the fact that theywill be easier to insert between the flanges of the profiles, since theflexible zone can be compressed. This is a particular advantage wheninsulation panels having layers of different densities are applied.

The distance between the profiles is dependent on the dimensions of theexternal cladding. Different types of external cladding are delivered indifferent dimensions. Often a distance in the range 54-61 centimetres isnecessary. Preferably the supplied insulation panels should be able tobe flexible enough so that only two different insulation paneldimensions are necessary.

Preferably, the insulation panels are attached to the inner wall bymechanical means such as nails or screws. However, any adhesives mayalso be applied. The mechanical means will anyway secure thatde-lamination of mineral wool insulation cannot take place.

The insulation material for the invention is preferably mineral woole.g. glass wool or stone wool. It may be delivered to the building siteas rolls or panels. When the insulation is of the stone wool type thelow density layer facing the inner wall will have a density below 50kg/m³, preferably below 45 kg/m³, even more preferably 20-40 kg/m³. Thehigh density layer facing the external cladding will (in the case ofstone wool) have a density of at least 70 kg/m³, preferably at least 80kg/m³ and even more preferably 80-120 kg/m³. The average density of theinsulation material will often be in the range 45-60 kg/m³.

Methods for manufacturing dual density insulation panels are describedin e.g. EP 1 111 113 A2.

The thickness of the insulation material will typically be in the range40-250 mm, preferably 50-200 mm. The thickness of the high density layeris 10-20 mm. When insulation panels are used these will typically have awidth of 400-700 mm, preferably closer to the actual distance betweenthe profiles, i.e. often in the range 500-600 mm. The length of thepanels is in the range 1000-2400 mm. When rolls are used these willpreferably have the same width, while the length will be longer butdependent on the thickness of the insulation.

The soft part of the insulation material facilitates the possibility ofadjusting to irregularities of the inner wall surface. Furthermore, thesoft part of the insulation offers the possibility of providing thepackages comprising the insulation material with some pre-compressionthus reducing the volume which have to be transported and thereby thecosts for transport. In order to facilitate the adjustment to the innerwall surface and the compressibility in packaging it might beadvantageous to apply the method described in WO 03/042445 A1 forsoftening the low density surface by mechanical depth wise compression,e.g. by rollers.

In a further embodiment of the invention an insulation panel having atotal thickness in the range 50-150 mm, preferably about 100 mm, ofwhich 15 mm has a density of 100 kg/m³, and the rest have a density of40 kg/m³, is being compressed on the low density major surface by apressing drum with a compression of 50%. Following this the product iscompressed 35% when packed.

If the same mechanical properties should be achieved by a mono-densityinsulation layer a density of at least 70 kg/m³ would be necessary. Suchinsulation would not be compressible.

In a preferred embodiment of the invention the insulation panel isprovided with at least one resilient or flexible minor edge surface.This means that the flexible minor edge surface is easily compressibleby hand, and is elastically compressible in such a way that removing thecompression will make the minor side surface of the board regainsubstantially its original dimension, however minor deviations from itsoriginal dimension should be expected. The rest of the board away fromthe flexible surfaces has a higher stiffness. The stiffness may bedefined according to EN826. Preferably, the whole minor edge surfaceshould be substantially equally flexible.

For manufacturing a mineral fibre panel with at least one flexible minoredge surface it must be realised that mineral fibre insulation comprisesa large number of individual fibres having different lengths anddiameters. For providing a stable mineral fibre board a binder is addedto the mineral fibres. Said binder is cured in a curing oven and willthereafter make the fibres stick to each other at the points where thefibres are in contact with each other. A method for making one or moreedge surfaces of this mineral fibre insulation panel flexible, i.e.elastically compressible, is to compress one or more rollers a distanceinto the edge surface. This compression by the roller will break some ofthe points of bonding in the mineral fibre board and thereby make theedge portion of the mineral fibre board softer and more elasticallycompressible than the rest of the board. The diameter of the compressionapplying roller(s) must be relatively small in order to concentrate thecompression forces in the desired region. The diameter is usually200-500 mm. The rollers are pressed a distance of 15-50 mm, preferablyat least 35 mm into the edge. The numbers of rollers would often be 1-7,preferably 2-4. The resulting depth of the flexible zone shouldpreferably be at least 35 mm, even more preferably at least 40 mm, inorder for two different dimensions of the insulation panels to cover thewhole possible span of possible distances between the profiles holdingthe outer cladding layer.

On the production line the panels will pass a zone where rollers arecompressed into the edge surface. Due to the high density layer of theinsulation panels often only one board passes the zone with rollers at atime, and often the board is supported on the majority of its top andbottom surface while passing the zone with rollers. Typically, therollers will extend different distances into the edge surface in orderto gradually compress the edge surface and thereby forming a morehomogenous resilient zone.

In a further embodiment of the invention three fasteners (typicallyscrews or nails) or less are used per square meter for fixation of theinsulation panels to the inner wall, preferably two fasteners are used,and even more preferably only one fastener is used per square meter. Anytype of adhesive could also be applied for this fixation.

The ventilation air gap will typically be in the range 20-150 mm,preferably 70-100 mm. Preferably, there will not be any points or areasof direct contact between the outer cladding layer and the insulationpanels. This will secure a free air flow in the ventilation air gap.

Especially for high buildings it is important to have openings forventilation in the façade and not just at the bottom and the top of theouter cladding layer. Preferably the openings are made by having a givenvertical distance between the external cladding panels, which willprovide the necessary openings for ventilation. The distance between theouter cladding panels is preferably in the range 5-20 mm.

In an embodiment of the installation of the building façade according tothe invention profiles e.g. T-profiles are attached to the inner wall,insulation panels having at least two layers having different densitiesand at least one flexible edge, are installed between the profiles.Finally, the external cladding layer is attached to the profiles,ensuring that an air gab is provided between the outer cladding layerand the insulation panels, and preferably with an opening in thevertical direction between the outer cladding panels.

In the following the invention will be described in more details withreference to the figures.

FIG. 1 shows a cross sectional view of the façade

FIG. 2 shows an insulation panel according to the invention.

FIG. 1 illustrates an example of a building façade (1) according to theinvention. The inner wall (2) is often made of concrete but also othertypes of material such as bricks may be applied. Profiles (10), e.g.T-profiles as illustrated, are secured to the inner wall (2) by e.g. 90degrees L-shaped fittings and screws (not shown). If U- or C-profileswere applied the profile would have a surface to be placed directlyagainst the inner wall and it could be attached directly with e.g.screws without extra fittings. However, this further surface of theprofile (10) would be placed against the inner wall along the wholelength of the profile (10). L-shaped fittings, however, would be placedwith certain distances. Therefore, a further surface on the profiles(10) might increase the cold-bridging slightly and, obviously alsoincrease the used amount of metal.

When T-profiles are applied the profiles have a base portion (7)extending perpendicular to the inner wall and joined to a flange portion(8) substantially parallel to the inner wall. The outer cladding issecured to the flange portions (8) of the profiles (10), e.g. by screwor nails (not shown), or in the case of metal plates for outer claddingalso welding could be applied.

The insulation is arranged between the base portions (7) of the profiles(10) in the vertical direction parallel to the inner wall, and theinsulation (3) is arranged between the inner wall and the outer claddinglayer in the vertical direction perpendicular to the surface of theinner wall (2). The insulation comprise layers (4, 5) of differentdensities, with a high density layer (5) facing the external claddingand a lower density layer (4) facing the inner wall. Along at least oneedge of the insulation, facing a profile (10) a flexible zone (9) isprovided. This zone is more easily compressible than the rest of theinsulation material.

Between the insulation and the outer cladding layer an air gab (11) isprovided for ventilation air. Air for ventilating this gab entersbetween openings between the outer cladding panels (6). The outercladding layer (6) should not be in direct contact with the insulationpanels (3).

FIG. 2 illustrates an insulation panel (3) according to claims 1 and 2of the invention. The insulation panel comprise two major surfaces (12,13) and 4 minor surfaces (14, 14′, 14″, 14′″). The high density layer,facing the outer cladding layer, preferably has a density of at least 70kg/m³, while the low density layer has a density below 50 kg/m³. Aflexible zone (9) is provided along one minor surface (14′) extending adistance perpendicular to the minor surface (14′) of at least 35 mm intothe insulation.

1. A building façade (1) having an inner wall (2), an insulation layer(3), an outer cladding layer (6) and profiles (10) for securing theouter cladding to the inner wall, where an air gab (11) for ventilationis provided between the insulation layer and the outer cladding, saidinsulation layer comprises insulation panels having two major largesurfaces (12, 13) and four minor edge surfaces (14), characterised inthat said insulation panels (3) have layers of insulation of differentdensities (4,5) extending parallel to the two major surfaces (12, 13),where a layer (5), with a density above an average density of the panel,is facing the outer cladding (6).
 2. A building façade according toclaim 1 characterised in that said outer cladding (6) comprises openingsfor ventilation air,
 3. A building façade according to claim 1 or 2characterised in that said insulation panel (3) is being flexible in atleast one direction parallel with the major surfaces (12, 13) so thatthe insulation panel is fitted closely against limiting surfaces.
 4. Abuilding façade according to any one of the claims 1-3 characterised inthat said insulation panels have a flexible zone (9) along at least oneedge (14′) in order to ensure that the panel is flexible in at least onedirection.
 5. A building façade according to any one of the claims 1-4characterised in that said insulation panels (3) are dual densityinsulation panels.
 6. A building façade according to any one of theclaims 1-5 characterised in that said insulation panels are made of afibrous material, preferably mineral wool and even more preferably stonewool.
 7. A building façade according to any one of the claims 1-6characterised in that said layer (5) with a density above an averagedensity of the insulation panel have a density in the range 60-130kg/m³, preferably 70-130 kg/m³, even more preferably 80-120 kg/m³.
 8. Abuilding façade according to any one of the claims 1-7 characterised inthat said layer (4) of the insulation panels (3) having the lowerdensity has a density below 60 kg/m³, preferably below 50 kg/m³, evenmore preferably 20-40 kg/m³.
 9. A building façade according to any oneof the claims 4-8 characterised in that the flexible zone (9) along atleast one edge (14′) of said insulation panels (3), has a depth of atleast 35 mm, preferably at least 40 mm, measured perpendicular to theminor edge surface (14′) of the insulation panel (3).
 10. A buildingfaçade according to any one of the claims 1-9 characterised in that thelayer (4) of the insulation panel (3) having the lower density is softand formable, so that it can adjust to irregularities in the inner wall(2) surface.
 11. A building façade according to any one of the claims1-10 characterised in that said profiles (10) are T-profiles comprisinga base portion (7) and a flange portion (8).
 12. A building façadeaccording to any one of the claims 1-11 characterised in that there isno points or areas of direct contact between the outer cladding layer(6) and the insulation panels (3).
 13. A building façade according toany one of the claims 1-12 characterised in that two or less fastenersare applied per square meter, preferably only one fastener is appliedper square meter.
 14. An insulation panel (3) suitable for applicationin the building façade (1) of claim 1 having two major large surfaces(12, 13) and four minor edge surfaces (14, 14′, 14″) comprising twolayers (4, 5) of different density parallel to the two major surfaces(12, 13), and an edge portion (9) along a minor edge (14′) surface,having a higher flexibility than the rest of the insulation panel (3).15. An insulation panel according to claim 14 characterised in that onelayer (5) has a density in the range 70-130 kg/m³, preferably 80-120kg/m³, and one layer has a density below 50 kg/m³, preferably 20-40kg/m³.
 16. An insulation panel according to claim 14 or 15 characterisedin that the edge portion (9) with a higher flexibility has a depth of atleast 35 mm, preferably at least 40 mm, measured perpendicular to theminor edge surface (14′).
 17. An insulation panel according to any oneof the claims 14-16 characterised in that the layer (4) having a lowerdensity is soft and formable, so that it can adjust to irregularities inthe inner wall (2) surface.
 18. A method for providing the buildingfaçade (1) of any one of claim 1-13, which method comprises thefollowing steps: attaching the profiles (10) to the inner wall (2),installing the insulation panels (3) according to any one of claim 14-17between the profiles (10), attaching the outer cladding layer (6) to theprofiles (10) ensuring that there are no areas of direct contact betweenthe outer cladding layer (6) and the insulation panels (3).
 19. A methodfor manufacturing the insulation panels (3) according to any one ofclaim 14-17 characterised in that the dual density insulation panels (3)passes a set of 2-4 rollers with diameters in the range 200-500 mm, therollers are pressed at least 35 mm into the edge surface (14′) of theinsulation panel (3).
 20. A method for manufacturing the insulationpanels according to claim 19 characterised in that the rollers willextend different distances into the edge surface (14′) in order togradually compress the edge.